The present invention relates to an electronic apparatus having programs and setting information.
The conventional electronic apparatus is comprised of a CPU (central processing unit), a non-writable and nonvolatile memory area for storing programs, a writable and nonvolatile memory area for storing setting information and a random access memory area used as a work area and most of them do not comply with update of programs. Therefore, electronic apparatus capable of complying with update of programs have recently been increasing in number.
A conventional electronic apparatus shown in block form in FIG. 6 is constructed of a CPU, a writable and nonvolatile memory for storing programs and setting information and a random access memory used as a work area so as to be able to comply with update of programs.
In FIG. 6, reference numeral 1 designates a CPU (central processing unit) for controlling the whole of the apparatus, 5 the writable and nonvolatile memory for storing programs and setting information, 6 the random access memory used as a work area, 4 a bus for coupling the CPU 1 to the memories 5 and 6, 51 a program area for storing the programs and 52 a setting information storage area for storing the setting information.
In FIG. 6, the area 51 for storage of programs is limited in number to one and in the event that an update of a program externally operated fails, the electronic apparatus cannot sometimes be started again. Further, in a conventional electronic apparatus not taking version up of programs into consideration, no mismatch takes place between the program and the setting information but in the case of an electronic apparatus considering version up of programs, such a restriction that a new program should not fail to understand the setting information till then is imposed on development of the apparatus when version up of a program is to be carried out, resulting in a problem that unless this restriction is met, the program cannot be started.
As described above, the conventional electronic apparatus face problems that when an update fails during update of a program in the electronic apparatus, the electronic apparatus is sometimes prevented from recovering and that the storage format of setting information must remain unchanged concomitantly with update of programs.
This type of electronic apparatus is therefore required to have ability to recover easily even in the event that the electronic apparatus fails to update version up of a program and ability to start without resort to special operation even when a change of program occurs that causes the storage format of the setting information to change.
An object of the present invention is to provide an electronic apparatus that can recover easily even when failing to update version up of a program and can start without resort to special operation even when a change of program occurs that causes the storage format of setting information to change.
To accomplish the above object, an electronic apparatus according to the invention comprises a central processing unit for controlling the whole of the apparatus, a writable and nonvolatile memory for storing programs and setting information and a random access memory used as a work area, wherein the nonvolatile memory includes at least three program areas.
With this construction, an electronic apparatus can be obtained which can recover easily even when failing to update version up of a program.